Plastic wiring duct, which is channel-shaped (having a bottom wall and a pair of spaced, vertical sidewalls), is used to route discrete electrical conductors and cable between predetermined locations. Such wiring ducts are typically manufactured by extrusion and are formed in the channel-shaped configuration. An example of such a duct is shown in United States Patent No. 3,890,459.
A relatively rigid channel shape is not particularly efficient for shipping purposes because the box containing the duct contains a high percentage of unfilled space. While a second duct can be inverted and positioned with one sidewall positioned between the sidewalls of the first duct, or ducts of progressively smaller size can be nested, the formation of such shipping arrangements requires the expenditure of additional labor and still results in appreciable empty space in the box. Of course, the shipping of a duct with so much air space makes the duct, although relatively rugged, more conducive to damage resulting from rough handling.